Abstract: To reveal the effect of γ-PGA application rate on the characteristics of single-point free soil water infiltration under film hole irrigation, infiltration experiment of different amounts of γ-PGA (0%, 0.1%, 0.5% and 1% ) was carried out, the effects of γ- PGA on infiltration rate, stable infiltration rate, cumulative infiltration rate, soil moisture distribution and infiltration wetting body were studied. The results showed that the free infiltration under γ- PGA application was in accordance with the Kostiakov model of soil water infiltration, and the infiltration rate decreased obviously, the stable infiltration rate decreased from 0.47 cm/ min to 0.15 cm/min, and the reduction rate reached 68%. The effect of γ-PGA amount on the migration characteristics of vertical wetting front was the most obvious, and vertical wetting front migration distance RX and infiltration time t accorded with the RX=D/2 + EtF model. The influence of γ- PGA on the moisture distribution of wetting body was obvious and the moisture content of wetting body in the 10 cm range of the center of film hole was significantly higher than that of CK, and increased with the increase of γ-PGA dosage, but water content change of each treatment layer was the opposite below 10 cm. The research results could provide reference for the future study of film hole infiltration.