Background staff's high turnover rate to the enterprise formed great capital loss, serious impact on the growth of enterprises, which cause the increasing research concern. A large number of existing research annotation task tired will staff resigned voluntary occur obvious effect, but existing research put attention task tired the resignation of volunteer outside the direct effect, less consider task tired on voluntary resigned the profound influence of mechanism. But some foreign newest research annotation task tired the resignation of volunteer is a connotation of psychological process under the influence of the process must be intermediary variables and conditioning variables combined action. Is, this study will task tired, psychological cost, organization commitment and resigned voluntary classified with a framework of analysis, discuss the task tired the resignation of influence mechanism of volunteer, assessment of organizational commitment and psychological cost in the influence mechanism of action, for the enterprise decline employees resigned supply rate of the new angle of view and the theory on which it is based, and has important practical significance and theoretical significance. Objective assessment of oil hair sell employees resigned the characteristics of voluntary; analysis of oil sales employees task tired, psychological cost, organization commitment and resigned voluntary relationship; to discuss organizational commitment in task tired and resigned between voluntary intermediary role; discuss psychological cost in task tired and vocation may the adjustment action, for the decline in oil sales staff resignation rate of actual supply according to. Way to take the basic personal situation query visit questionnaire, task fatigue scale, psychological cost query visit questionnaire, organizational commitment scale and resigned volunteer scale of Sinopec Beijing branch oil company made sales staff survey, issued a total of 500 questionnaires, recycling effective questionnaire 429. Application of SPSS17.0 software to establish a database and data processing, statistical methods have adopted descriptive analysis, variance analysis, t training, coherent analysis, regression analysis etc.. Achievements: 1. From a population variables on: 25 years old the following oil sales staff in resigned on voluntary score was significantly higher than that of 26-35 years old and above 36 employees (P < 0.001); length of service for 1-3 years of oil sales staff, in resigned voluntary score was significantly higher than that of 3 years or more employees (P < 0.05); monthly spending in 2000 yuan of the following and 2000-3000 yuan oil hair sell employees in resigned on voluntary score was significantly higher than that of the more than 3000 employees (P < 0.001). 2. Oil sell employee task tired and dimensions and resigned volunteer was significantly positive correlation (P < 0.001); psychological capital and its dimensions and resigned volunteer was negatively related (P < 0.01); organizational commitment, emotional commitment, standard promise and resigned volunteer was negatively related (P < 0.01). 3. Organizational commitment in task tired and resigned voluntary relationship plays a partial mediating effect and mediating effect accounted for the proportion of the total effect is 20%. 4 psychological cost has obvious effect on fatigue and a conditioning task volunteer relationship (R2=0.054, P<0.05). Conclusion the 1 oil sales staff younger, monthly expenditure is lower, the higher the degree of voluntary resignation. 2. The task tired the resignation of volunteers has significant positive forecast effect and organizational commitment in task tired and resigned volunteer plays a part of the intermediary role. 3. Psychological cost in task tired and resigned voluntary relationship from negative to the conditioning effect, namely high psychological cost of oil hair selling staff, similar in the level of task tired, whose resignation volunteer lower.