The aim of this study is to specify the experiment objectives in the biological field of Middle School Sciences (I) changed according to the textbook revision in `84 School year and to develop the effective experiment-oriented teaching and evaluating methods, making use of these specified objectives. The specific objectives of this study are as follows; 1) to specify each experiment objectives in accordance with the general objectives of science subjects. 2) to apply the specified experiment objectives to criterion-referenced experiment classes. 3) to develop the proper evaluation methods and test items according to the specified objectives. The research design of this study is composed of three stages; First, in the above-mentioned objective 1), the objectives of biological lessons in the first grade of middle schools are specifically presented. Second, to examine the students performance changes and interest response in order to achieve the objective 2) Third, to develop the test items appropriate to the new evaluation methods of each unit and present their best usages in order to attain the objective 3). The results of this study can be Summarized as follows: 1) To develop the specified experiment objectives and grasp the picture of how the experiment lessons in each unit are distributed in the fields of preens skills such as observing, classifying, measuring, inferring, predicting, formulating hypothesis, variable controlling, etc. 2) To develop a new experiment lesson plan and its guide-report, applying the specified objectives. 3) The conventional evaluating methods were inclined to emphasize the cognitive domain, but here, the new test items are developed to evaluate not only the experimental skills but also the psychomotor domain and affective domain. The evaluating area consists of the cognitive domain (60%), the affective domain (20%) and the psychomotor domain (20%). 4) The most part of the process skills in these experimental lessons prove to belong to observing and classifying. 5) The students in the experimental class show the mole increase of 15% in their interest response and higher marks by 13 in their summative test than those in the controlled class.