In order to describe the object’s shapes steadily by chordal distribution in object’s region

region main chord and it’s perpendicular scanning chords were defined firstly in the paper and their computation method was put forward. Object region chordal distribution is composed of main chord and perpendicular scanning chords. According to main chord and perpendicular scanning chords length and position

the paper defined such effective shape features as chordal area

parallelism degree

edge points symmetry proportion

main chord length and chordal square rate. Finally

the paper used these region chordal features dealing with some simple shapes and cell images.The result showed that these features can distinguish round

ellipse

rectangle

parallelogram and anomalistic polygon. At the same time the cell identifying ratio was improved and misjudgment ratio depressed obviously after the cell region’s chordal features were used in microscopical cell image classifying and recognition system.The system distinguished the shapes among strip tube cell and quadrate rime and round cell and anomalous epithelia effectively.