Zhang, J. 2008. A relative weight model for soil productivity assessment. Can J. Soil Sci. 88: 827Á832. Soil productivity is a function of inherent factors such as topography, parent material, physical and chemical properties of the soil, and the infrastructure for irrigation and drainage. As multi-criteria evaluation methods in soil productivity assessment, the leastfactor and weight methods, while popular, have limitations. The least-factor method is not accurate enough in the absence of a vital constraint factor, and the weight method leads to an inaccurate, and even incorrect result when there is a vital constraint factor. In order to overcome these limitations a new concept, relative weight, was introduced and a prototype model developed. In this prototype model, every factor has different relative weights in different soil units, thus allowing it to overcome shortcomings of the Weight method where the weights of a given factor are assumed to be equal in all soil units. This prototype model was then applied in a case study on the Loess Plateau in Northwest China. Results from the case study indicated this prototype model was more precise than either the least-factor or weight methods, and was able to avoid the invalid results of the Weight method.Key words: Soil productivity index, relative weight, multi-criteria evaluation, Loess Plateau Zhang, J. 2008. Mode`le a`ponde´ration relative pour l'e´valuation de la productivite´du sol. Can. J. Soil Sci. 88: 827Á832. La productivite´du sol de´pend de facteurs inhe´rents comme la topographie, le mate´riau d'origine, les proprie´te´s physiques et chimiques ainsi que l'infrastructure d'irrigation et de drainage. Aussi populaire qu'elles soient pour e´valuer la productivited u sol a`partir de crite`res multiples, la me´thode du plus petit facteur et la me´thode de ponde´ration ont leur limites. La premie`re n'est pas assez pre´cise sans facteur de contrainte vital alors que la seconde aboutit a`des re´sultats impre´cis, sinon errone´s, en pre´sence d'un tel facteur. Pour surmonter ces obstacles, l'auteur propose un nouveau concept, la ponde´ration relative, et a mis au point un mode`le expe´rimental. Dans ce mode`le, chaque facteur posse`de une ponde´ration relative diffe´rente selon l'unite´de sol, ce qui permet de surmonter les carences de la me´thode de ponde´ration qui pre´sume l'application d'un meˆme facteur de ponde´ration, peu importe l'unite´de sol. Le mode`le expe´rimental a e´te´applique´a`une e´tude de cas sur le plateau Loess, dans le nord-ouest de la Chine. Les re´sultats re´ve`lent que ce mode`le est plus pre´cis que les deux pre´ce´dents et permet d'e´viter les re´sultats errone´s de la me´thode de ponde´ration.