Abstract: Liu and Nebesky have independently provided different necessary and sufficient conditions for the upper embeddability of graphs. This paper mainly investigates the upper embeddability of bipartite graphs. We prove the following result:（1）Let G=(X,Y;E)and G³=(V(G³),E(G³)), where V(G³)=V(G),E(G³)=E(G)∪{e=xy|d_G(x,y) = 3,x∈ X,y∈ Y}, then G³ is up-embeddable； (2)Let G=(X,Y;E),|X|=|Y|=n(n≥ 3), for every pair of x∈ X,y∈ Y with d_G(x,y)=3, such that d(x)+d(y)≥ n+1,then G is up-embeddable.

Key words: Bipartite graph, Bettti deficiency, Upper embeddable, Maximum genus, Bipartite graph, Bettti deficiency, Upper embeddable