To improve the ratio of the power of in-phase mode to the total power of output signal (Q) for the 19-core fiber laser, two improved methods are presented. In the first improved scheme, three pieces of undoped fiber, with the same structure and numerical aperture as the ytterbium-doped 19-core fiber, are introduced into the Talbot cavity of the fiber laser. In the second improved scheme, the output beam from the single mode fiber laser is transformed to match the in-phase mode using the double convex lenses. The improved schemes are numerical simulated and analyzed based on a set of rate equations. The ratio Q and the output power of each mode are investigated for different parameters such as the distance between fiber ends (a), the power refraction factor of mirror on the signal output end (RM2), and the pump power. The quantitative analysis shows that, for the first scheme, the optimum distance a exists for the fixed RM2, and the Q can be increased from 79.06% to 88.25%; For the second scheme, the ratio Q can be increased to 95.74%, which ensures better beam quality.