There are many methods to measure soil permeability, however, each method shows some defects when used on the biocrustal (biological soil crusts) soil on slope lands. Line source infiltration method is a simple and rapid method for the measure of infiltration on slope land without biocrusts. In this study, the water infiltration processes of bare soil (control) and different types of biocrusts, including cyanobacteria dominated, cyanobacteria-moss mixed and moss dominated biocrust soil in the Hilly Loess Plateau region were tested by using line source infiltration method. Meanwhile, the simulated rainfalls were applied on the same plots to get the permeability of the soils. The results showed that:(1) The line source infiltration method can describe the water infiltration process quickly and completely without disturbing the biocrusts. Meanwhile, the parameters such as initial infiltration rate, average infiltration rate and stable infiltration rate were observed stably. (2) The initial infiltration rate range of different types of biocrust obtained by the line source infiltration method in the study area was 3~12 mm/min, the average infiltration rate range was 0.5~4.5 mm/min, and the stable infiltration rate range was 0.3~1.8 mm/min. With the increase of moss coverage, the initial, average and stable infiltration rates were significantly different. (3) There was a significant linear correlation between the stable infiltration rates of biocrusts soil measured by the line source infiltration method and those of the simulated rainfall (y=1.73x-1.24, R²=0.376 8, ρ =0.539^*). This study provides a simple and easy method for the determination of water infiltration rate in biological crusts soil on slope lands.