The evolution of hot-image formation in consideration of focusing lens effect is theoretically and numer-ically investigated. Through analysis of linear propagation theory with lens, it is shown that the locationof hot image in focusing systems can be predicated through definite functional relation to hot imageposition in non-focusing systems, on condition that the distance between the hot image and the lens isrelatively small. In addition through numerical calculation, specific variation characteristics of maximumintensity with the propagation distance representing hot-image formation process are presented, it isobtained that perturbing scatter size directly affects the location and corresponding peak intensity ofthe hot image. The lens influences the value of scatter size where minimum distance between hot-imageplane and focus lens is generated. Finally, the effects of phase and amplitude modulation of scatter on hotimage are also given. Results in this paper are of fair referenced value for controlling perturbing scatterand restraining the damage risk of optical components in focusing systems.