A solid state storage device and sensing voltage setting method thereof are provided, and the method includes following steps. A predetermined read voltage of the memory cells is adjusted to obtain a plurality of detection read voltages. The predetermined read voltage and the detection read voltages are respectively applied to a plurality of memory cells in order to read a plurality of verification bit data. A plurality of statistical parametric values between the predetermined read voltage and the detection read voltages adjacent to each other is calculated and recorded according to the verification bit data corresponding to the predetermined read voltage and the detection read voltages. An optimized read voltage is obtained according to the statistical parametric values.