The invention relates to a temperature closed-loop control method for a steam type lithium bromide absorption water chilling unit. By the adoption of the method, temperature closed-loop and pressure closed-loop cascade control of cold water can be achieved, and single-loop independent control can also be achieved. For temperature loop outer-loop PID control parameters, the control strategy that proportionality coefficient, integral coefficient and differential coefficient can change intelligently according to the difference value between actual cold water temperature and set cold water temperature is realized, so that system response time is shortened, ideal cold water temperature is obtained quickly, and cold water temperature control precision is improved. For pressure loop inner-loop PID control parameters, the variable-structure PID algorithm is used as the core algorithm of a pressure controller, and the opening control method is adopted when the error is large, so that it is guaranteed that a system works stably and cold water temperature can be adjusted to a set value step by step; when the error is small enough to be within a certain range, the control structure is changed automatically, the position type PID algorithm is adopted to eliminate the static error and improve the control precision of the system, and then the control targets of saving electricity and saving energy are realized.