In the TRAMS_RUC_1km (Tropical Region Assimilation Model for South China Sea _ The Rapid Update Cycle _ 1km) model, the initial field and lateral boundary condition scheme was revised (including its vertical resolution, time update frequency and completeness) and tested with a typical squall line case. Preliminary analysis revealed: (1)The meso-scale character of precipitation in squall line was better simulated after increasing vertical resolution of initial field and lateral boundary, while increasing vertical resolution of middle and low layers played the most critical role in it. (2)The diurnal change of lateral boundary forcing got more accurate after increasing its time update frequency. The squall line moved south after using high frequency updated boundary condition, because of the convergence of moist flux alone coastline was strengthened. (3)With high vertical resolution and high update frequency of lateral boundary condition, lateral forcing of vertical speed and cloud particle had no obvious impact on forecast of squall line. In general, it was important to increasing the vertical resolution of initial field and lateral boundary field, the time update frequency was also needed to be increased, while the lateral forcing of vertical speed and cloud particle could be omitted. The impact of new scheme was verified against observation in April of 2019 (last for a month). The distribution pattern and diurnal cycle of mean hourly precipitation were improved significantly with the revised initial and lateral condition.