Objective　To evaluate relationship among oropharynx injury and a number of factors during general anesthesia by a binary Logistic regression, we aim to clinically instruct selecting appropriate sizes of laryngeal mask and improve streamlined liner of the pharynx air-way (SLIPA) laryngeal mask insertion technology.　Methods　Two hundred and eighty eight patients between July 2014 to May 2015 who were undergoing distal extremities open reduction and internal fixation were enrolled in this study. An identical laryngeal mask general anesthesia combined with nerve block was used in all patients, spontaneous respiration was maintained during surgery. The dependent variable is oropharynx injury while 6 independent variables including climax of resistance, shaping of SLIPA, help from assistants, body weight, selected SLIPA sizes according to the width of oropharynx, body weight, whether small sizes were used, etc. All the factors entered into the final model of the stepwise logistic regression analysis were included in a separate Logistic regression model. Logistic regression was performed by PASW Statistics 18.0 statistical software to investigate possible associations between oropharynx injury as dependent factor and multiple independent factors. Also, the weight of each independent variable is estimated.　Results　Univariate analyses were performed and showed three factors leading to oropharynx injury during SLIPA laryngeal mask general anesthesia, including climax of resistance, shaping of SLIPA, whether SLIPA sizes were selected according to the width of oropharynx or not (P<0.01). Binary Logistic regression analyses results showed a significant positive correlation between oropharynx injury and climax of resistance, shaping of SLIPA, whether SLIPA size were selected according to the width of oropharynx, whether laryngeal small sizes were used. Peak resistance above 32 N during SLIPA insertion could cause 56 times higher risk of oropharynx injury than the risk when the resistance below 32 N. Inserting SLIPA without shaping could cause 22 times higher risk of oropharynx injury than risk of the opposite. Choosing SLIPA size without pre-measuring the width of the oropharynx caused 7.6 times higher risk than the risk of the opposite. Choosing relatively bigger SLIPA size could cause 4.3 times higher risk than the risk of smaller size.　Conclusions　Oropharyngeal hemorrhage caused by insertion of SLIPA is notably related to the high resistance during the insertiong process. Shaping SLIPA, selecting SLIPA size according to the width of oropharynx, and choosing smaller size can reduce the risk of oropharyngeal bleeding and injury in anesthetized patients without muscle relaxants.