From local firms' perspective, we propose a learning model of locals within multinational companies network, and also do an empirical study on the two determinants of local firms' learning effectiveness, which are its social capital and absorptive capacity（ACAP）. Furthermore, the mediator roles of local firms' knowledge accessibility and relative absorptive capacity have been found out. The results indicate that our model is fit basically; both social capital andabsorptive capacity have no direct impact on learning effectiveness of local firms. Interorganizational trust of social capital has significant impact on the outcome through the mediator of knowledge accessibility. However, we found out that the relative absorptive capacity not only influences learning effectiveness directly, but also plays a mediator role significantly.