Abstract: Multifunctional land use is the objective requirement of land use efficiency improving and social and economic sustainable development. The evaluation of land use functions is a basic work for multifunctional land use. After discussing the classification of land use function, the paper established an evaluation index system based on three-dimensional sustainable development of economics, environment and socity, and then measured the state of land use functions in 1990, 2000 and 2010, as well as the change during the 20 years in Guangzhou by using the grey relation projection evaluation model with the indexes reflecting the state and change of land use function, such as realization rate, dynamic degree, standard deviation and dominance. Furthermore, the obstacle indicators of land use function were analyzed via obstacle degree model. The results show that: 1) The dynamic degree of total function was 14.1% and 15.6% during 1990-2000 and 2000-2010, which indicated that the total function had slowly improved. The standard deviations of single function and subfunction increased gradually, which denoted that the harmony of multifunction was weakening. With the decrease of the dominance, land use functions become more diversified. The function that changed the most was the environmental function during 1990-2000 and the social function during 2000-2010, which meant that the kernal function of the land use changed from the environment in the former period to the society in the latter period. 2) The change characteristics among functions are different. For the single function, the economic function and social function jumped from slowly improving to rapid promotion, while the environmental function falled from rapid promotion to slowly improving during 1990-2000 and 2000-2010. 3) In the 10 subfunctions, agricultural production and resource supply continuously degenerated, environment purification firstly decreased and then increased, and other functions improved in different degree from 1990 to 2010, including economic development, transportation, ecological maintenance, provision of work, social security, living conditions and leisure culture. 4) As view from the index layer, factors which have impacts on the total function of land use were in dynamic changes, so were the categories and number of obstacle factors and the obstacle degree. The obstacle factors evolved from economic concerning type such as economic density to resources and environmental type, such as wastewater discharge intensity, per capita cultivated land, etc. Finally, the study indicates that the evaluation index system and model established in the paper is effective, and it enriches the research of multifunctional land use. The study provides the method and scientific basis for land use function evaluation and the decision support for multifunctional land use in the future in Guangzhou.