Biodiesel is a promising alternative fuel or in combination with petroleum diesel for environmental benefits. In this study, the biodiesel used is Jatropha oil, which is manufactured from jatropha curus by trans-esterification process using KOH as catalyst. The performances and emission characteristics of jatropha blended with diesel along with butanol (n-butanol) is studied. The butanol additive is mixed with B20 (20% of biodiesel +80% of diesel) in various proportion and analysed in Kirloskar TV-1 engine. A minor increase in brake thermal efficiency with significant improvement in reduction of smoke density, hydrocarbon (HC), carbon dioxide (CO2) compared to diesel. It has also little effect on reduction of NOX and CO. The use of trans-esterified Jatropha oil and its blend will reduce the dependence on fossil fuels and also decreases considerably the environment pollution.