This letter presents a method to convert the split dual-beam into a single one in the quasi-E-plane with low cross-polarization level for the pin-loaded fundamental EH0-mode microstrip leaky-wave antennas (MLWAs). By exciting a pair of them under differential operation with proper configuration, the φ-polarized dual beams can be reshaped to achieve a single-beam radiation, so as to widen its potential application. The proposed method for transversal single beam still preserves the merits of the original pin-loaded EH0-mode MLWA with simple structure and freely designed narrow width. A prototype MLWA with single-beam radiation in the quasi-E-plane is designed, fabricated, and measured. Good agreement is attained between simulated and measured results, and thus validates the unique feature of the proposed method in design of single-beam pin-loaded EH0-mode MLWAs.