Based on constructal theory, a heat dissipation model of two-dimensional double-sided square column discrete heat sources on a heat conduction base in a jet channel is established. The total longitudinal section area and the height of the discrete heat sources are set as the constraints, the optimization objectives are as follows: minimizing the maximum temperature, the temperature uniformity factor and the temperature gradient uniformity factor of the system, and the length ratio between each heat source is set as the optimization variable, then the effects of the jet speed and the heat source spacing on heat dissipation are analyzed. When the heat source spacing and jet speed are given, the maximum temperature, the temperature uniformity factor and the temperature gradient uniformity factor of the system can be reduced by changing the length ratio between the heat sources. When the heat source spacing and the length ratio between heat sources are given, with the increase of the jet velocity, the maximum temperature, the temperature uniformity factor and the temperature gradient uniformity factor of the system all decrease at different degrees.