With the increase of the population，the demand for the house is also increasing. Because of the rapid rise in housing prices of the newly built houses，it is beyond the capacity of most consumers. Therefore，the consumer began to turn to the second-hand housing market，and the demand for second-hand housing also increased. According to the monitoring and investigation data of the price index of new and second-hand houses in 70 large and medium-sized cities in 2017，this paper estimates and analyzes the new and the second-hand housing sales price index density curve by using the non-parametric kernel density estimation method. The results show that the demand of the new housing and the second-hand housing is the same，there is a correlation between the two，and the rise in the price of new housing has a certain driving effect on the rise of second-hand housing prices，and second-hand housing has gradually begun to dominate in the housing market.