To improve the flexural properties and reduce the risk of brittle out-of-plane failure in masonry walls， ultra-high ductile concrete （UHDC） layers were introduced to strengthen the masonry members. Four-point bending tests were carried out on seven strengthened masonry members in this study. The failure mode， bearing capacity and deformability of the specimens were comparably analyzed. The experimental results indicated that ductile failure modes were achieved in masonry specimens strengthened with single- and double-sided UHDC layers， and the strengthened specimen showed ductile bending failure modes. The UHDC layers had satisfied restraint effect on masonry flexural members， which can significantly improve their flexural capacity and deformability. The increase of the thickness of UHDC layer could effectively improve the ultimate bearing capacity. The contribution of UHDC layer in tension zone to the flexural bearing capacity was less than that of UHDC layer in compression zone. Finally， the formulas of calculating the flexural capacity of masonry flexural members strengthened with single- and double-sided UHDC layers were individually proposed， providing a design basis for masonry flexural members strengthened with UHDC.