This study explores linguistic features, ideological beliefs, and critical thinking in news comments, which are defined as the comments from readers to news posts on social media or platforms. Within the overarching framework of critical discourse analysis, a sociocognitive approach was adopted to provide detailed analyses of the studied constructs in sampled news comments. In terms of the data collection and analysis, sampled social media, news columns, and news comments were selected, and then 19 college students were interviewed for their responses to different news topics. The primary findings of the study include: (1) personal and social opinions are representations of ideological beliefs and are fully presented through news comments, (2) these personal and social ideological beliefs may diverge or converge due to critical thinking, (3) critical thinking helps commenters form their personal and social ideologies, and then helps them choose the linguistic forms they believe fit their news comments, (4) news topics, however, vary in informing commenters’ critical thinking ability. Finally, a sociocognitive model for studying linguistic forms, ideologies, and critical thinking was proposed in the study.