The eldest son of top Chinese leader Deng Xiaoping, on a private tour of the United States to learn about programs for the disabled, is showing a high profile during his five-day stay in Washington.

Since his arrival in the capital Tuesday, Deng Pufang, who uses a wheelchair, has met with President Reagan and Secretary of State George P. Shultz. He attended a dinner hosted by Vice President Bush and his wife, and lunched on Capitol Hill with leading senators.

The purpose of the three-week private visit is for Deng, founder and head of the China Fund for the Handicapped, to learn about U.S. facilities and programs for people with disabilities. But, said one State Department official, "Obviously, we believe his father will follow the visit and pay attention to the kind of reception he gets."

Deng, 43, has been a paraplegic since 1968, when, at the height of the political turmoil of the Cultural Revolution, he was forced out of a fourth-story window while he was a physics student at Beijing University.

In the past few years, he has emerged as an articulate advocate for the disabled and is widely credited with improving conditions for the 40 million to 50 million disabled in China, reported to be the largest such community in the world and one that the Chinese historically have treated with contempt. Until recently, the Chinese word for a person with a disability was canfei, which literally means incomplete and useless. The fund has since adopted a more respectful term, canji ren, which means incomplete person.

Deng is a strong advocate of humanism, a concept that has come under attack by China's orthodox Marxists. The capitalist countries, he has said, have done more than China for the physically disabled because they have a greater respect for individuals. And a political regime and social system, he has argued, are most often judged on their social welfare records.

At a press conference yesterday, Deng said he hoped his U.S. visit would help his efforts back home to "let society understand, be concerned about and respect" people with disabilities.

In response to questions, he also said a party congress scheduled to open later this month would "strengthen the policy of reform and opening to the outside world," an effort that has been led by his father.

In a brief interview after the news conference, Deng said many people who are worried about political stability in China "don't understand Chinese society." Those with a deeper understanding, he explained, "have more confidence in China's stability."

Looking relaxed and smoking a cigarette, the younger Deng, with a crewcut and western suit, also said his father was in "very good" health. The secret to his father's health, he said with a laugh, was his passion for "smoking, drinking, and eating hot peppers." His father stayed in shape, he added, by playing bridge and swimming.

Deng, who is visiting the United States for the first time, arrived in New York last week. Plans for the trip began two years ago, but because of the younger Deng's poor health, the visit was postponed last year, according to officials of the National Committee for U.S.-China Relations, the trip's sponsor.