"联立方程模式" can be translated into English as "system of simultaneous equations model" or simply "simultaneous equations model".
"System of simultaneous equations" refers to a set of equations that are considered together and solved simultaneously, as they are interdependent.
"Model" is added to indicate that this is a mathematical or theoretical representation used for analysis or prediction.
Both expressions are commonly used in academic and professional contexts, especially in economics, statistics, and applied mathematics.