This paper considers the sparse linear array (SLA) design problem of coherent unambiguous transmit for the distributed aperture coherence-synthetic radar (DACR), accounting for the antenna size constraint and geography constraint in which elements can not be placed in a given aperture. We develop the peak sidelobe level (PSL) based cost function, which considers the sum of the PSL when the mainlobe located at all scanning angles. Then, we derive the antenna element locations by minimizing the cost function through PSO algorithm. Finally, several numerical simulations verify the effectiveness of the proposed SLA design method.