Abstract: The mathematical model about the quantization of ADC are usually based uniform quantizer, and the effects of the front anti-folding filter is always ignored. the correlation characteristics of the pseudo-random code in spread spectrum receiver, an universal quantization model and theoretical formula of quantization loss is established , which can be applied to uniform and non-uniform quantization. When the filter is neglected, the quantization formula can be predigested to a more straightforward form. Numerical result show that the loss incurred by the front filter and that by quantization can be separated when the front filter is ignored and sampling rate is equal to the Nyquist rate. Finally, numeric results are listed, which can be used to direct the design of DSSS receiver.