Abstract: This paper takes a 37.6 km two-way four-lane fi rst-class highway bidding by a city, studying the control and management strategy of the preliminary cost of road engineering in PPP model. By analyzing the profi t model under PPP model, a quantitative analysis model through model analysis method was studied, and a deep quantitative analysis of the PPP primary highway project bidding by the city through case analysis method was conducted, and fi nally found many practical problems. This paper fi nally believes that: under the PPP mode, the bidding department should do enough work in the bidding process and cost reserve, and require the relevant departments to cooperate closely, in order to obtain a more detailed and eff ective preliminary project cost results.