The present descriptive study aimed to investigate the find out the degree to which the teachers of the first field employ the principles of constructivist theory in teaching linguistic patterns and the obstacles to their employment. To achieve the aim of the study, the researcher prepared two instruments : the observation card, which consisted of (28) teaching practices that measure the degree of employing the principles of constructivist theory in teaching linguistic patterns and a questionnaire, the first part of which consisted of (28) teaching practices, and the second part aimed at knowing the obstacles to employing the principles of constructivist theory in teaching language patterns, and it contained (22) obstacles, and their validity and reliability were confirmed, and the stability coefficient of the observation card reached (88.0) according to the Cronbach's alpha coefficient and (96.0) according to the Pearson's coefficient. And the questionnaire reached its stability value (80.0) according to the Cronbach's alpha coefficient. The results of the study showed that the teaching practices of the principles of constructivist theory in teaching linguistic patterns ranged between a high and a very high degree, and that the obstacles faced by the teachers of the first field in employing the principles of constructivist theory came to a medium degree, and the results of the study showed that there are statistically significant differences. It is attributed to the variable of experience in favor of (10) years and above. Accordingly, the study recommended the formation of a specialized committee from the Ministry of Education to study the obstacles facing the teachers of the first field in employing the principles of constructivist theory, and based on that, it suggested conducting studies, including analyzing the content of Arabic language curricula activities according to the principles of constructivist theory.