The lottery has both public welfare attributes and entertainment attributes. Research on the entertainment function of the lottery helps to promote the high-quality development of the lottery industry. This paper sorts out the international definition of lottery，makes a detailed analysis of the entertainment motives of different types of lottery games sold in China，and builds a formula for the conservation of lottery entertainment value on this basis，believing that only healthy and green sales are the true embodiment of the social entertainment value of the lottery，and the existing lottery games cannot fully meet the market demand，and need to innovate in theory and practice.