The invention discloses a method for detecting a comprehensive titer of low-grade coal degradation liquid. The method comprises the following steps: detecting influences of the low-grade coal degradation liquid on multiple representative optimum parameters in crops seed germination and growth processes, and converting into a comprehensive biological titer through comparative study so as to characterize the overall regulating effect of the degradation liquid on the crop growth and development. Compared with a chemical analysis method, the method disclosed by the invention is capable of intuitively and accurately detecting the overall regulating effect of the low-grade coal degradation liquid on the plant growth and development, and is high in stability, high in applicability and high in degree of standardization. Meanwhile, the method is easy to operate, short in time and low in cost, is applicable to large-scale popularization and application, fills the gap of a low-grade coal degradation liquid activity detection method and removes a great obstacle for the popularization and application of the product as well as industrialization development.