The study purposes to analyze mathematics national examination (UN) items, which are guessed to be multidimensional, with MIRT to see test dimensions and item parameters. The analysis is expected to conclude quality of item and test more precisely. This study will examine the response patterns of 3299 DIY students who work on 40 multiple choice mathematics questions package 1 in UN in 2015. The research process begins with Principal Component Analysis (varimax rotation) analysis, analysis fit model of test with signed chi-squared, estimating parameters based on on the dimention of factors according to the results of the PCA, and the conclusion. The results of the analysis show that the Mathematics Examination Package 1 is divided into 3 factors, there are several items that measure more than one ability, and there are 1 items that must be removed because the difficulty level (MDIFF) is in the very easy category.