Abstract: The local displacement transducer(LDT) represents a latest measurement technique in triaxial test.The LDT can be used to increase the precision of strain to 0.001%(10 -5 ) and to measure the deformation characteristics accurately and continuously in a strain range from less than 0.001% to 1% in a single test.This paper studies the relationships between modulus and strain level or stress level in a small strain range.Some beneficial conclusions are obtained.