Housing is one of the essential contributing factors to the growth of the economy. "Despite its importance, however, the housing sector has not received adequate attention from macroeconomists.“ (Zhu, 2014) Housing studies in general cover two areas - housing demand and housing supply. Compare with housing demand, researchers have noted that housing supply is understudied (Green, et al, 2005) probably due to the deficiency of micro-data of housing supply which embraces supply quantity and supply time. By gathering 885 housing projects from the official property registration platform in Shanghai, China, this paper focuses on examining how the time of housing supply is determined, more specifically the determinants of the first period of time* from land supply to housing supply. After analysing the generalized property development model and undertaking multiple linear regressions, we find that government is a major party in influencing the times of housing supply. Firstly, the permits and certificates required by various government or government related agents in the process largely determine the length of construction and marketing. Secondly, the three independent variables, i.e. plot area, plot ratio and housing price, are all significant at 1% level. Relatively speaking, plot ratio exerts bigger impacts than the other two on the dependent variable of the first period of time with a coefficient of 4.63. The results prove that government could play a vital role in housing supply.