In view of the complex stability calculation of double-row steel sheet piles in soft soil foundation, based on the theory of soil mechanics, the control analysis was carried out from the aspects of anti-uplift stability, overall anti-slip stability, anti-overturning stability, and overall sliding stability of the sheet pile. By theoretical derivation and calculation, the calculation formula of the minimum penetration depth Ld of steel sheet piles is given. Taking the double-row steel sheet pile cofferdam project of the sluice of the Oufei Reclamation Project in Zhejiang Province of China as a case, according to the formula in this paper, the recommended minimum depth of soil penetration is 17.01m, which is basically the same as the actual design value of 18.50m. Combined with the finite element soft foundation, the comparative analysis of simulation calculation results and the measured horizontal displacement monitoring data of steel sheet piles provides references for related engineering applications.