Drawing upon data from the 2008 Chinese General Social Survey ，this paper examines the impact  of  China ’s family  planning policy  on people ’s  sense  of  happiness ，with  the  number  of  siblings  as the proxy  of  the family  planning policy  effect． Research  findings  are  summarized  as follows : ( 1) The  sense  of happiness of  the  post － 80  generation  is  significantly  reduced  with  the  increase  of  the  number  of  siblings ; (2) Among brothers and  sisters ，the number of  the elder brothers is the  most  prominent  determinant  in  reducing the  sense of  happiness ; ( 3) As for the middle － aged  and  older  people ，reduction  in  the  number  of children has no  significant  influence on their  subjective well － being． In the  context  of  scarcity  of  education and  social  security  resources ，China ’s  family  planning  policy  has  enhanced  rather  than  reduced  people ’ sense of  happiness． Hence ，future adjustment  of  the family  planning  policy  could further  improve  people ’s happiness by  addressing gender  imbalance ，ageing and decreasing labour  supply．