It is obvious that qualities of software design heavily affects on qualities of software ultimately developed. One of claimed advantages of object-oriented paradigm is the ease of maintenance. The main goal of this work is to propose a methodology for constructing maintainability model of object-oriented software design model using three techniques. Two sub-characteristics of maintainability: understandability and modifiability are focused in this work. A controlled experiment is performed in order to construct maintainability models of object-oriented designs using the experimental data. The first maintainability model is constructed using Metrics-Discriminant technique. This technique analyzes the pattern of correlation between maintainability levels and structural complexity design metrics applying Discriminant analysis. The second one is built using Weighted-Score-Level technique. The technique uses a weighted sum method by combining understandability and modifiability levels which are converted from understandability and modifiability scores. The third one is created using Weighted-Predicted-Level technique. Weighted-Predicted-Level uses a weighted sum method by combining predicted understandability and modifiability level, obtained from applying understandability and modifiability models. This paper presents comparison of maintainability models obtained from three techniques.