The two-dimensional snake scanning of the CCD method provides an effective solution to measure small-scale light spots which are smaller than one CCD pixel. The influences of the A/D conversion digits and response uniformity of the CCD on the measurement error are studied. When the A/D conversion digit is 20, the measurement error can be ignored. The maximum error value of the nonuniform response of the CCD pixel when the order of the super-Gaussian function is 10 is 0.7 μm. The research results can be used to guide the experiment.