Evaluation of the fine particle effect on frozen soils is important since natural deposits in cold regions comprise particles of various size. The goal of this study is to evaluate the strength and shear wave velocity of frozen soil mixtures for the estimation of the silt fraction effect. A shear box incorporated with k-type thermocouple and bender elements is designed for the test. The specimens with silt fractions of 0, 30, and 70% by weight (Wsilt/Wsand × 100%) are mixed and placed into the shear box at the fixed relative density of 60% and degree of saturation of 15%. The specimens are frozen to −5 °C, and the direct shear test is conducted after freezing. Tests show that the peak and residual shear strengths change according to the silt fraction. The shear wave velocity rapidly increases after freezing and gradually decreases during shearing. Both the shear strength and shear wave velocity indicate minimum values at a silt fraction of 30%. This study demonstrates that the consideration of silt fraction should be carried out since fine particles in frozen soil mixtures may change the strength and stiffness.