Nano-resolution imaging based on single molecule localization is simulated with Matlab. A sample consisted of several lines of molecules are simulated imaged. The results demonstrate that two lines of molecules separated by 20 nm can be resolved. Effect of pixel size on the localization accuracy is also discussed here. Nano-resolution imaging is realized on an IX71 inverted fluorescent microscope with the resolution (FWHM) of 48 nm. Nano-resolution images of filopodias are reconstructed, in which filopodias with diameter of 75 nm are resolved.