Abstarct: In recent years, the spread of various pollutants related to the environment, including heavy mextals and other emerging dangerous pollutants, is considered a serious concern. therefore, detection of mextals is very important in order to deal with pollution. In this research, Rhodamine B dye was hydrazined first, and after this step Rhodamin B hydrazide (RBH) was prepared with 3- and 4-dihydroxybenzaldehyde. (3,4-DHBA) reacted and at the end of this synthesis product, which is rhodamine B hydrazide 3,4-dihydroxybenzaldehyde (RBH-3,4-DHBA), was treated with acryloyl chloride (ACCL). The structure of the sensor prepared by instrumental analysis methods is determined and its application is used in the measurement of mextal cations. In the following, the response of the prepared sensor in the face of various mextal cations is studied by UV-Vis and photoluminescence spectrophotometric methods. The effect of various factors, such as sensor concentration, mextal ion concentration, pH, solvent effect, etc. , in the response of the sensor is investigated. After this step, the synthesis of the prepared sensor (RBH-3,4DHBA+AC) with the environmentally friendly polymer N-vinyl pyrrolidone (NVP) and methyl methacrylate (MMA) along with the initiator of the azoisobutyronitrile (AIBN) reaction in the solvent Dimethyl formaldehyde (DMF) was placed under N2 gas and the reaction temperature was 70 0C and the reaction time was 24 hours. After the end of this step, add 3 grams of polymethyl methacrylate (PMMA) to the contents of the container obtained from the synthesis of the previous step. The reaction time is 2 hours. After 2 hours, we take the prepared polymer inside the container to prepare fiber for electrospinning. After that, the prepared sensor is fixed on the polymer and the performance of the sensor is checked in the solid phase. For this purpose, polymer nanofibers can be used to increase the specific surface area, increase the sensitivity, and increase the detection sites, thus increasing the response speed. At this stage, UV-Vis, FT-IR, SEM, EDX, DSC, TGA, etc. spectrophotometric methods are used to analyze and determine the structure of the prepared sensor. Parameters such as selectivity, detection limit, quantification limit, linear range and application of the prepared sensor in the aqueous phase are studied.