A computer implemented blend control system and method for preparation of a hydrocarbon blend from a plurality of component streams have been disclosed. The system includes a product tank for receiving a mixture comprising the plurality of component streams. The system further includes a sensor and analyzer adapted to sense and analyze a first attribute of the received mixture for obtaining a first attribute data. The system further includes an optimizer which stores the attribute based model data, receives the first attribute data and compares the received first attribute data with the attribute based model data to compute an optimized proportion data, based on which the component streams are selectively drawn into the product tank for preparing the hydrocarbon blend.