Convergence theory is a primary topic in topology. In fact, topology and so-called convergence class are characterized by each other. In fuzzy topology (L-fuzzy topology), more than 40 papers published in the last ten years were concerned with convergence theory. Among these papers, the problem of convergence class was solved for the case ofL=[0,1] [7]. Since the neighbor structure, so called “quasi-coincident neighborhood system,” of anL-fuzzy point in anL-fuzzy topological space is in general not directed under the inclusion order, the conditions of convergence class in [0,1]-fuzzy topology will not be valid any longer in the case of lattice. Moreover, quite different from the cases of {0,1}-fuzzy topology (i.e., ordinary topology) and [0,1]-fuzzy topology, the so called Bolzano–Weierstrass property does not hold, i.e., a net with a cluster point in anL-fuzzy topological space is not still necessary to have a subnet converging to the point. In this paper, a necessary and sufficient condition for the Bolzano–Weierstrass property is produced, the result is also used in a satisfactory theory of convergence classes inL-fuzzy topological spaces, and the associated characterization theorem betweenL-fuzzy topologies and convergence classes is established.