Blogs are useful interaction tools to promote learners’ knowledge construction and interaction in online teaching activities. On the other hand, although many studies show that mindtools facilitate learners’ cognitive process, little research focus on their effects on learners’ higher order cognitive thinking in blogs. This research developed a learning environment by using a mindtool-based blog to promote learners’ higher order cognitive thinking in their online discussions and to assess their learning effects. The participants were 276 senior high school students from an information ethics class. A quasi-experimental research design was adopted in this research. The control group used the ordinary blogs. The Experimental Group 1 used the basic mindtools in blogs, which means that learners can use all the mindtool functions except the Knowledge Compilation function. The Experimental Group 2 used the advanced mindtools in blogs, which means that they can use all the mindtool functions, including the Knowledge Compilation function. The results indicated that both experimental groups showed better learning effects and more higher order cognitive thinking than the control group. Moreover, the higher order cognitive thinking category Analyze was found more often in the Experimental Group 2 than in the Experimental Group 1.