In order to investigate the effects of sandy soil and mixed biochar on water and salt transport and tomato growth characteristics in saline-alkali soil under drip irrigation, field plot experiment was carried out with three treatments, including control (CK), sand hole (T1), and sand hole mixed with biochar (T2), analyze the effects of sand holes on soil moisture, salinity distribution and tomato growth characteristics under drip irrigation. The results showed that the distribution of soil moisture and salinity in different treatments was extremely uneven. The average water content and EC value of each treatment in the sand area were CK > T2 > T1. Soil salinity mainly migrated to the bare area between plant and plant, showing a high value area of EC, and the location of the high value area was different. In the section below drip irrigation belt, T1 and T2 all desalinated in 0-80 cm soil, CK accumulated salt in 0-40 cm soil and desalinated in 40-80 cm soil. Root volume under T2 was 3.00 times larger than that under CK, and showed trend as T2 > T1 > CK. The highest yield was 57.37 t/hm² under T2, which was 80.78% higher than that of CK. The yield of each treatment shown as T2 > T1 > CK, and sand hole had a significant effect on tomato quality. In conclusion, T2 can significantly improve soil infiltration, inhibit soil salt return, improve soil water and salt status, and promote crop growth. This study provides theoretical basis for agricultural development and utilization of saline-alkali land.