A laser diode (LD) dual-end pumped, conductively cooled, electro-optical Q-switched composite Nd:YAG laser is designed. Double-pulse laser output with adjustable pulse interval is achieved. By using two fiber-coupled LD modules as the pumping source, β-BaB2O4 (BBO) crystal as the Q-switch, double-pulse laser output is acquired by opening the Q-switch twice in a pumping cycle time, and the laser is capable of producing two Q-switched 1064 nm pulses with the single pulse energy more than 14 mJ, 18 ns, the interval between the two pulses is adjustable from 200 μs to 230 μs at the repetition of 50 Hz, the optical-to-optical efficiency reaches 24%. Furthermore, we explore the feasibility of stable double-pulse laser output by using the Q-switched crystal KD2PO4 (KD*P), and suppressing the piezoelectric ring effect of KD*P, the sub-pulse phenomenon is removed and double-pulse laser output with 11 mJ, 18 ns, is obtained.