The high-precision all optical quantization technology based on soliton self-frequency shift (SSFS) effect is investigated. It is still unclear whether this technology is able to achieve high-precision quantization although some experimental results have been reported. Investigating the properties of SSFS effect by simulation, it is found that for a soliton pulse with optimal t=150 fs, the number of bits (NOB) can be up to 8 with the effective number of bits (ENOB) equal to 7.02. Narrower pulse width cannot obtain the same NOB whereas wider pulse width affects the linearity of the quantization function and reduces the ENOB. A pulse width of 150 fs requires a bandwidth of 9.8 nm and an average power of 0.92 W under 50 GHz sampling pulse rate, which is within the capability of current optical technologies. Chirp broadens the pulse width and reduces the NOB and ENOB significantly and thus should be avoided.