The technology life cycle, the scale of investment and the risk of investment are the factors influencing the development of hi-tech industry. This paper indicated that a good relationship between public investment and private investment is very important to the development of high-tech industry in the informationalized society. This paper firstly analyzed public investment and private investment on hi-tech industry, then used the society return rate to analyze the change of hi-tech industry. Public investment should make up for the shortage of private investment.