The start at the Aintree course in Liverpool will be moved forward 90 metres, further from the crowd, and measures will be introduced to stop horses getting caught up in the starting tape.
The landing zone of the famous Becher's Brook jump will be levelled out and fence designs will be reviewed, the BHA said on their website.
Two horses, Cheltenham Gold Cup winner Synchronised and According To Pete, died in the race on April 14 this year, the second successive year there had been two fatalities.
The deaths led to questions about the safety and future of the race and criticism from animal rights organisations.
Aintree Racecourse and the BHA believed the course could continue to accommodate a maximum of 40 runners but they would monitor the issue of field size, the BBC reported.
In this year's race, Synchronised and 28-1 outsider According To Pete had to be put down after meeting grief at Becher's Brook during the four-and-a-half-mile race.
Synchronised had already unseated champion jockey Tony McCoy as they approached the starting area. Vets cleared him to run after examining him but the race was delayed, with a number of false starts.
Neptune Collonges eventually won the 165th running of the race in a photo finish from Sunnyhillboy.
According to the BHA, 10 horses have died in the Grand National in the last 12 years while 20 horses have died since 2001 over the Aintree fences in other races.