A one-dimensional (1D) edge-emitting photonic crystal laser is designed based on the ridge waveguide of organic conjugated polymer poly[2-methoxy-5-(2-ethylhexyloxy) phenylenevinylene-1,4-diyl] (MEH-PPV) and the special optical modulation characteristics of photonic crystals. The band gap structure and the band edge effect of photonic crystal are employed to construct the resonator formed by photonic crystal total mirror and partial transmission mirror. 1D photonic crystal defect component is introduced on the ridged waveguide in the resonator and suppresses effectively the mode competition based on the property of photonic crystal defect-mode. The boundary-mode effect caused by composite structure is analyzed, and empirical formula for the cavity length of this kind of non-metallic microcavity laser is obtained. The simulating result shows that a single longitudinal mode laser output with the central wavelength of 588 nm and the full width at half maximum of 0.131 nm is achieved in 1D edge-emitting organic photonic crystal laser.