Recently, two new plant species have been introduced in Guilan province as invasive weeds, water hyacinth (Eichhornia crassipes (Mart.) Solms) and perennial ragweed (Ambrosia psilostachya DC.) that are very important in word due to their environmental effects. Weed Risk Assessment (WRA), rankes weeds according to botanical characteristics, environmental impacts and their extent for their management plans. According to final score, three solutions are provided for each weed: 1- rejection or denial of the presence of invasive weed and preventing the entry or eradication of it, 2- further evaluation of that plant and accepting that the plant is a low risk weed, 3- accepting the presence of that invasive plant in that area. In this study, Weed Risk Assessment of two invasive weeds in Guilan province, aquatic hyacinth and western ragweed was calculated. According to WRA system western ragweed with 175.2 score has high risk weed and urgent management practice are necessary to prevent more spread. Aquatic hyacinth was also high risk with weighing 116.66.