Subpixel imaging is one of the effective ways to increase spatial resolutions of optical imagers by reducing frequency aliasing caused by the sampling process of discrete sensor grid. This paper presents a novel subpixel imaging system with linear CCD sensors. The system is consisted of a specially designed focal-plane-assembly(FPA) with two 2048 pixel linear CCD, a CPLD(Complex-Programmable-Logic-Device)-based controller, analog signal chain, and related image processing software. Firstly, analysis of the relationship between MTF and subpixel displacement is conducted, with quantum results presented, and the design of the FPA are analyzed. Secondly, we reviewed related image deconvolution algorithms, and discussed the precision image registration and improved Wiener filtering algorithm for this system, potentials of wavelet-based image restoration are also invoked. Preliminary pushbroom tests of a prototype subpixel imaging system show that the resolution of the subpixel system is 1.5~1.6 times greater than that of conventional system at Nyquist frequency, considerable resolution improvment has been obtained.