Abstract: The technology of automated fiber placement (AFP) in-situ crystallization for thermoplastic composites is the key point for efficiently and inexpensively manufacturing large composite components. However, because the processing parameters have a great influence on the mechanical properties, to ensure the mechanical properties of laminates made by AFP in situ crystallization, the processing parameters should be analyzed and optimized. The prepreg made of polypropylene as matrix and continuous glass fiber as reinforcement (GF/PP) was used to produce laminates through the AFP platform. Influences of the processing parameters, such as temperature of hot gas, lay-up pressure of hot roll and cold roll, and furthermore, their interaction effects on the mechanical properties were analyzed based on the theory of response surface methodology. A quadratic polynomial regression equation was set up to forecast the relationship between the processing parameters and the mechanical properties. The effectiveness and reliability of regression model were verified through the test analysis such as predicated versus actual. Furthermore, the optimal process parameters of AFP were obtained:temperature of hot gas is 385℃, lay-up pressure of hot roll is 0.3 MPa and lay-up pressure of cold roll is 1.1 MPa.