The new type coupler with chain link connection was a new type of differential coupler, which had the ad vantage of curve lateral flexible swing. It was mainly used in North American rolling stock. It was an important part of rolling stock parts system. According to the product structure, design requirements, technical difficulties and functional requirements of the new chain coupler, casting CAE simulation technology was used to optimize the casting process design. The new chain coupler has been successfully trial-produced. through product testing, the mass supply has been realized.