The present study related to the agro-ecological analysis of the area catchment Okoriko in the district of Toui at Ouèssè (department of the hills). The degradation of the resources through the operating systems is at the origin of the analysis agro-ecological to understand the evolution of the catchment area. From this analysis, an inventory of the various agricultural activities undertaken by the population of the catchment area was made, an evaluation of the impact of the agricultural activities on the environment is also made. The data processing collected on the ground, made it possible to note that in the area catchment Okoriko, the principal operating systems are : agriculture, fishing, the breeding, and forestry exploitation. Agriculture and the forestry exploitation are the most practised activities and occupy more half of the population. Indeed, more than 67 % of the ecosystems are occupied by agricole lands and nearly 10 % of the population have their activity directed towards the forestry exploitation. Only 21 % of the households undertake activities like the breeding, and fishes it. These activities are factors of pollution water, ground, vegetation, watery fauna.