A method for collinear nanosecond double-pulse lasers with an adjustable pulse delay and energy ratio is proposed. Lamp-pumped collinear nanosecond double-pulse Nd∶YAG lasers were built for verification. The performances of single-pulse mode and double-pulse mode laser outputs were compared, and the influence of voltage applied to the electro-optical crystal on the pulse energy and time waveform was studied. The time interval between the two pulsed lasers can be controlled from 100 ns to 10 μs, hence satisfying the requirements of the majority of double-pulse lasers. Double-pulse lasers share a resonant cavity and therefore exhibit inherent coaxiality, which is ideal for obtaining collinear double-pulse lasers and can be extrapolated to other lasers.