With the enhancement of technological complexity, assessing technology objectively is becoming more and more difficult. On basis of the philosophical connotation of assessment, this paper conveys that the hypostasis of assessment is to reveal the value-relation between value-subject and object. Value is essentially the special relation between value-subject and object, which is also the relation that between the property and function of value-object and needs of the value-subject. Secondly, Weinberg rule of science option and the objective meaning of technological complexity are introduced and the associations between them are constituted on basis of philosophical connotation of assessment. Weinberg interior criteria and exterior criteria which contains technological value criteria, scientific value criteria and social value criteria are associated with the three levels of technological complexity which is the technology module complexity, mutual action of technological complexity and complexity of mutual action. Thirdly, this paper probes into constituting the needs of value-subject with Weinberg Rule in view of holding the needs of value-subject, and probes into the meaning of technological complexity in view of the cognition of the property and function of value-object and expatiates on Weinberg Science Option Rule in view of technological complexity. At last, this paper applies the criteria of science option to constitute the assessment criteria framework for assessment of basic research, applied research, experimental development and framework of S&T project evaluation in the S&T assessment practice.