By conducting meta-analysis on the researches of relationship between income level and happiness at home and abroad, this paper researches the relationship between income level and happiness. The results show that the relationship between income level and happiness takes on U-shape curve, and it can be explained from adaptation, social comparison and psychological expectation. Finally, in order to promote rural residents' income level and strengthen rural residents' happiness in China, corresponding policy suggestions are put forward as follows: bridge gap of urban-rural residents' income distribution; dilute the competitions for money and status among people; perfect rural social security system; endeavor to create a situation in which ail rural residents do their best.