Abstract: Based on the comprehensive analysis of currently used three methods for calculating soil modulus in pile foundationi.e., laboratory test, empirical correlation based on previous experience and back- figuringmethod from pile-loading test, a new simple approach to compute soil modulus by back analysis from single pile load-settlement curve is putforward, and charts and formulas are also presented for practical engineering use. Practical example analysis shows that the soil modulus obtained by back analysis from single pile load curve should be used as the parameter for calculating when elastic theory is employed to calculate the pile groups settlement.