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A tunable efficient quasi-phase matched second harmonic generation (SHG) in nonlin ear LiNbO3 crystal has been demonstrate, where the distribution of ferroelectric domains possess only the short-range order.In such domain structures the reciprocal vectors form a series of concentric rings.In each ring the reciprocal vectors are continuously distributed, which can be used to compensate continuous wave vector differences and achieve the phase-matching for different frequencies and multiple parametric interactions.Therefore, the tunable output can be realized with higher conversion efficiency.This process is similar to the broadband SHG in random media, but the existence of short range ordered domain results in much higher frequency conversion efficiency.