The invention discloses an optimization method for vehicle path planning of an assembly type construction site. The method comprises the following steps: defining important elements in a fabricated construction site vehicle path optimization problem, setting parameters, and converting two-dimensional coordinates of a construction site into an Euclidean distance matrix; running an ant colony algorithm, performing probability operation of selecting a next access stacking point according to a roulette selection algorithm, and continuously performing pheromone updating; and, according to the genetic algorithm, encoding three important parameters alpha, beta and rho in the ant colony algorithm which are used as dyes, after the optimal combination of alpha, beta and rho is obtained through crossover and mutation operation, taking the optimal combination as an input parameter and then substituting the input parameter into the ant colony operation, and after finite iteration is performed, finally obtaining the optimal path of the vehicle. According to the method, the iterative performance and the optimization efficiency of the model are improved, a local optimal solution is prevented frombeing obtained, and meanwhile, the convergence speed of the model is increased, so that the method is greatly helpful to the scheduling optimization problem of prefabricated part transport vehicles ina prefabricated building site.