A new global optimization algorithm (Powell-DE algorithm) was introduced. Powell algorithm with strong local search ability was integrated into the differential evolution algorithm to overcome shortcomings such as slow convergence and the tendency to fall into local optimum. Meanwhile, typical test function simulation was used to test and compare Powell-DE algorithm and to verify the effectiveness of the algorithm and reflect the superiority of the new algorithm. Then, Powell-DE algorithm was used to soft measure the NK concentration on the basis of LSSVM model in the evaporation process, and was compared with the other two methods. The new model shows better track performance and high accuracy, and can be applied to the online prediction of the NK concentration of the feed solution.