NOVELTY - Upgrading hydrocarbon involves cracking hydrocarbon in presence of catalyst to provide cracked mixture having light cycle oil and coked catalyst; mixing second hydrocarbon having 4-20C hydrocarbon (A1) with catalyst to provide mixture; introducing third hydrocarbon to provide additional coke on coked catalyst; cracking second hydrocarbon in presence of catalyst to give second cracked mixture having propylene and hydrocarbon (A1), and second coked catalyst; and combining two mixture to give third mixture.    USE - For upgrading hydrocarbon (claimed) e.g. naphthas and other light hydrocarbon useful to provide olefins, cycle oils, and high-octane blend stocks.    ADVANTAGE - The catalyst uses in the method has improved olefinic hydrocarbon concentration and increased research octane number of the cracked hydrocarbon compounds, thus the method improves the production of olefinic hydrocarbon    DETAILED DESCRIPTION - Method for upgrading at least one hydrocarbon involves cracking a first hydrocarbon in the presence of at least one catalyst at a first temperature to provide a first cracked mixture comprising at least one light cycle oil and a first coked catalyst; mixing a second hydrocarbon comprising at least one 4-20C hydrocarbon (A1) having a research octane number of less than 88 with the at least one catalyst to provide a first mixture at a second temperature; introducing a third hydrocarbon to provide additional coke on the first coked catalyst; cracking a second hydrocarbon in the presence of the catalysts at a second temperature to provide a second cracked mixture comprising propylene and at least one hydrocarbon (A1) having a research octane number of greater than 88, and a second coked catalyst; and combining the first cracked mixture and the second cracked mixture to provide a third mixture comprising the light cycle oils, the propylene, the hydrocarbons (A1) having a research octane number greater than 88, the first coked catalyst and the second coked catalyst.