The combination of sieve method and laser grain size analysis to analyze grain size of total load is the fundamental method for grain size analysis. The phenomenon of results of two series of grain size analysis intercrossed always occurs. It is necessary to research the correction of grain size of total load. This paper puts forward the correction method of grain size and the integrating methods of two series of grain size analysis, supposes that firstly adopting sieve method to analyze sediment, and then analyzing the finer sediment (the part with grain size smaller than the dividing line, namely, smaller than the size of adopted sieve) with laser grain size analyzer, two chances are possible that the ratio of mass to volume, of the part with grain size smaller than the dividing line, analyzed with laser grain size analyzer, is equal to 1 (100%) or smaller than 1 (100%). The paper also analyzes the disadvantage of two correction methods, of which the first is adopting the dividing size of sieve method as basis and the second is adopting the maximum grain size analyzed with laser grain size analyzer as basis. Finally, the paper draws the conclusion that the part actually exceeding the scope of laser grain size analyzer is smaller in mass and it is reasonable to adopt the method put forward in the paper to correct the grain size and getting rid of the contradiction of results of two series of grain size analysis intercrossed.