In order to investigate the effects of organic additives as well as the influences of short-circuit resistance to the characteristics of D.C. tree in low density polyethylene, observations on the inception voltage and growing characteristics of D.C. tree with several different short-circuit resistances are carried out on the specimens blended with the additives such as, aniline, m-cresol and p-dichlobenzene respectively. As the results, the observed characteristics with zero short-circuit resistance is mainly related to, so-called, "short-circuit tree''''which is formed at the step of the short-circuit procedure due to strong poisson field resulted by space charges in the vicinity of the needle electrode. Furthermore, this kind of tree shows the distinct polarity effect such that the inception voltage in case of positive polarity on needle electrode is larger than that of the case of negative polarity. On the other hand, the observed characteristics with high short circuit resistances such as 20 and 200 Kohm respectively, are related to "impressed tree" defined as that to be formed while the pressure is impressed at electrodes, and those kinds of tree shows a clear inversed polarity effect compared with the case of zero short-circuit resistance. As a whole it is concluded that, as a voltage stabilizer, aniline is a more effective inhibitor to short-circuit tree, while, m-cresol is a more effective one to impressed tree.