This paper proposes an approach for solving integrated assembly sequence planning and assembly line balancing with ant colony algorithm. In integrated assembly sequence planning and assembly line balancing, the assembly task priority diagram is built based on the assembly information, and the assembly sequences are evaluated in each workstation of the assembly line separately; for calculating the total assembly time in the workstation, besides the assembly task time, the time for changing assembly directions, changing assembly tools, and the time for moving the heavy parts in the workstation are also considered. The fitness function is built and the constraints are discussed; an ant colony algorithm is proposed to carry out assembly sequence planning and assembly line balancing simultaneously, based on the searching mechanism and the pheromone updating mechanism, to obtain the optimal solutions under the given cycle time. Finally, case studies are given to verify the proposed approach.