Maintenance problem for infrastructures such as bridge, road, airport, etc., attracts keen interest in modern Japan. We have to cope with repair and maintenance for infrastructures with limited financial resources. In airport pavements, repair works are restricted by daily flight operation, so that efficient maintenance planning is required. In this paper, we try to model deterioration of an existing airport runway, which is composed of 100 units. PRI (Pavement Rehabilitation Index) for each unit is obtained by 3 to 8 times of inspection during around 28 years. PRI is an index to provide an objective evaluation of pavement surface condition, with criteria determined for judging the need for rehabilitation work on runway, taxiway, and apron pavements. Many researches and practitioners use PRI for airport pavement maintenance in Japan. The spatial distribution of deterioration in airfield pavement is not discussed in many previous studies. This study discusses deterioration curve for each unit and feature of spatial distribution. The distribution of deterioration based on PRI and the probability of exceedance of each PRI criteria in future are estimated by the proposed method.