As one of the most important key words in ethical literary criticism, scientific selection as theory is not equivalent to scientific choice as terminology in critical practice. The former refers to the third stage of choices after the natural selection and ethical selection, mainly tackling the problem of the combination of science and humans; while the latter focuses on the action of choice based on scientific norms. No matter in reality or in science fiction, the results of scientific selection exist everywhere. With the narration in science fiction of robots, androids, human cloning and immortality, the paper attempts to sort out the denotation and connotation of this keyword, helping to understand humans' cognition and transformation to nature. However, the scientific choice narrated in the novels is still the result of humans' ethical consciousness and ethical choice, which refers to the initial stage of scientific selection. The real scientific selection means a stage where science replaces ethics, that is, by virtue of technological products, humans develop from human extension to human deconstruction and turn into "humans by scientific choice". Strictly speaking, scientific selection, separating from ethics, has not yet arrived; nonetheless, science fiction has expounded how humans develop and use technology from the perspective of scientific choice, predicting the impacts and consequences science has exerted on humans, thus prompting us to consider the hybrid and coexistence of science and humans in the future. [ABSTRACT FROM AUTHOR]