Buffer influences the performance of production lines greatly.To solve the buffer allocation problem(BAP) in serial production lines with unreliable machines effectively,an optimization method is proposed based on an improved ant colony optimization(IACO) algorithm.Firstly,a problem domain describing buffer allocation is structured.Then a mathematical programming model is established with an objective of maximizing throughput rate of the production line.On the basis of the descriptions mentioned above,combining with a two-opt strategy and an acceptance probability rule,an IACO algorithm is built to solve the BAP.Finally,the simulation experiments are designed to evaluate the proposed algorithm.The results indicate that the IACO algorithm is valid and practical. Buffer influences the performance of production lines greatly.To solve the buffer allocation problem (BAP) in serial production lines with unreliable machines effectively, an optimization method is proposed based on an improved ant colony optimization (IACO) algorithm. Firstly, a problem domain description buffer allocation is structured. a mathematical programming model is established with an objective of maximizing throughput rate of the production line. On the basis of the descriptions above, combining with a two-opt strategy and an acceptance probability rule, an IACO algorithm is built to solve the BAP. Finaally, the simulation experiments are designed to evaluate the proposed algorithm. The results indicates that the IACO algorithm is valid and practical.