Based on the rural sample data from the China Family Panel Studies (CFPS2016),this paper empirically analyzes the impact of social network on the livelihood diversification of rural families and the law of its impact changes in the accelerated marketization process.The results show that firstly,livelihood diversification as an effective way for families to cope with the impact of future income fluctuations is prevalent in rural areas of China; secondly,the richer the social network,the higher the level of rural families’livelihood diversification; thirdly,with the acceleration of rural marketization,the impact of social network on livelihood diversification of rural households is gradually weakening.It is increasingly difficult for rural households to diversify risk and reduce livelihood vulnerability through social network.Therefore,it is proposed to continue to promote the reform of rural financial system,develop inclusive finance,improve the coverage and quality of financial services to farmers,especially for poor farmers,so as to meet the long-term requirements for smoothing consumption and avoiding risk of rural households.